1. Technical Field
The present invention relates to an electro-optical device and to an electronic apparatus. More particularly, the present invention relates to an electro-optical device that has a favorable sound-production function when being provided in a portable electronic apparatus.
2. Related Art
In general, electro-optical devices are provided in various electronic apparatuses. Further, there are many cases in which the electro-optical devices are provided in various electronic apparatuses together with sound-production units, such as speakers or the like. In an electronic apparatus according to the related art, typically, an electro-optical device (for example, a liquid crystal display device) is housed in a case, while being separated from a sound-production unit. For example, in a portable electronic apparatus, such as a cellular phone, the electro-optical device and the sound-production unit are separately mounted on a substrate that is disposed in the case (for example, see Japanese Unexamined Patent Application Publication No. 2001-168963) or the electro-optical device and the sound-production unit are directly fixed to separate places in the case (for example, see Japanese Unexamined Patent Application Publication No. 2002-77346).
Further, in order to reduce the size and the thickness of a portable electronic apparatus, as the sound-production unit mounted in the above-described electronic apparatus, a piezoelectric sound-production unit is used in which a piezoelectric vibrating body formed by laminating a vibration plate, and the piezoelectric body is fixed to the case (for example, see Japanese Unexamined Patent Application Publication No. 2002-77346).
In addition, a small electronic apparatus has been suggested in which a liquid crystal panel and a backlight device disposed at the rear of the liquid crystal panel are housed in an apparatus case, a speaker is disposed in a backlight case of the backlight device, and a sound-guiding path is provided in the backlight case so as to guide the sound from the inside of the backlight case to the sound output slot of the apparatus case (for example, see Japanese Unexamined Patent Application Publication No. 8-168037).
In recent years, with the progress of the reduction in size of portable electronic apparatuses and the increased screen size of display devices, in the structure disclosed in Japanese Unexamined Patent Application Publication No. 2001-168963 or 2002-77346, if a display section and a sound-production section are disposed in such a way that they overlap each other, the thickness of the case is inevitably increased. On the other hand, when the display section and the sound-production section need to be disposed in such a way that they do not overlap each other to reduce the thickness of the case, there is problem in that the size of the apparatus is inevitably increased.
Further, in the structure disclosed in Japanese Unexamined Patent Application Publication No. 2001-168963 or 2002-77346, when the sound-production unit is disposed in the electronic apparatus, acoustic design in the vicinity of the sound-production unit needs to be performed for each case. Accordingly, the design of the case may be restricted. Further, there is a problem in that a sufficient reduction in size or thickness of the case cannot be achieved.
In addition, in the configuration disclosed in Japanese Unexamined Patent Application Publication No. 8-168037, since the speaker is disposed in the backlight case, the sound-production space of the speaker is restricted by the structure of the backlight case, and thus optimum acoustic design is difficult to perform. On the other hand, in view of the acoustic effect when the backlight case is designed, there is a problem in that the optimization of the optical characteristics of the backlight is difficult to achieve.